Update: Translations from eints

[openttd-github.git] / src / gfx_layout.cpp

/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file gfx_layout.cpp Handling of laying out text. */

#include "stdafx.h"
#include "core/math_func.hpp"
#include "gfx_layout.h"
#include "string_func.h"
#include "strings_func.h"
#include "debug.h"

#include "table/control_codes.h"

#include "gfx_layout_fallback.h"

#if defined(WITH_ICU_I18N) && defined(WITH_HARFBUZZ)
#include "gfx_layout_icu.h"
#endif /* WITH_ICU_I18N && WITH_HARFBUZZ */

#ifdef WITH_UNISCRIBE
#include "os/windows/string_uniscribe.h"
#endif /* WITH_UNISCRIBE */

#ifdef WITH_COCOA
#include "os/macosx/string_osx.h"
#endif

#include "safeguards.h"


/** Cache of ParagraphLayout lines. */
Layouter::LineCache *Layouter::linecache;

/** Cache of Font instances. */
Layouter::FontColourMap Layouter::fonts[FS_END];


/**
 * Construct a new font.
 * @param size   The font size to use for this font.
 * @param colour The colour to draw this font in.
 */
Font::Font(FontSize size, TextColour colour) :
                fc(FontCache::Get(size)), colour(colour)
{
        assert(size < FS_END);
}

/**
 * Helper for getting a ParagraphLayouter of the given type.
 *
 * @note In case no ParagraphLayouter could be constructed, line.layout will be nullptr.
 * @param line The cache item to store our layouter in.
 * @param str The string to create a layouter for.
 * @param state The state of the font and color.
 * @tparam T The type of layouter we want.
 */
template <typename T>
static inline void GetLayouter(Layouter::LineCacheItem &line, std::string_view str, FontState &state)
{
        if (line.buffer != nullptr) free(line.buffer);

        typename T::CharType *buff_begin = MallocT<typename T::CharType>(str.size() + 1);
        const typename T::CharType *buffer_last = buff_begin + str.size() + 1;
        typename T::CharType *buff = buff_begin;
        FontMap &fontMapping = line.runs;
        Font *f = Layouter::GetFont(state.fontsize, state.cur_colour);

        line.buffer = buff_begin;
        fontMapping.clear();

        auto cur = str.begin();

        /*
         * Go through the whole string while adding Font instances to the font map
         * whenever the font changes, and convert the wide characters into a format
         * usable by ParagraphLayout.
         */
        for (; buff < buffer_last && cur != str.end();) {
                char32_t c = Utf8Consume(cur);
                if (c == '\0' || c == '\n') {
                        /* Caller should already have filtered out these characters. */
                        NOT_REACHED();
                } else if (c >= SCC_BLUE && c <= SCC_BLACK) {
                        state.SetColour((TextColour)(c - SCC_BLUE));
                } else if (c == SCC_PUSH_COLOUR) {
                        state.PushColour();
                } else if (c == SCC_POP_COLOUR) {
                        state.PopColour();
                } else if (c >= SCC_FIRST_FONT && c <= SCC_LAST_FONT) {
                        state.SetFontSize((FontSize)(c - SCC_FIRST_FONT));
                } else {
                        /* Filter out non printable characters */
                        if (!IsPrintable(c)) continue;
                        /* Filter out text direction characters that shouldn't be drawn, and
                         * will not be handled in the fallback case because they are mostly
                         * needed for RTL languages which need more proper shaping support. */
                        if (!T::SUPPORTS_RTL && IsTextDirectionChar(c)) continue;
                        buff += T::AppendToBuffer(buff, buffer_last, c);
                        continue;
                }

                if (fontMapping.count(buff - buff_begin) == 0) {
                        fontMapping[buff - buff_begin] = f;
                }
                f = Layouter::GetFont(state.fontsize, state.cur_colour);
        }

        /* Better safe than sorry. */
        *buff = '\0';

        if (fontMapping.count(buff - buff_begin) == 0) {
                fontMapping[buff - buff_begin] = f;
        }
        line.layout = T::GetParagraphLayout(buff_begin, buff, fontMapping);
        line.state_after = state;
}

/**
 * Create a new layouter.
 * @param str      The string to create the layout for.
 * @param maxw     The maximum width.
 * @param fontsize The size of font to use.
 */
Layouter::Layouter(std::string_view str, int maxw, FontSize fontsize) : string(str)
{
        FontState state(TC_INVALID, fontsize);

        while (true) {
                auto line_length = str.find_first_of('\n');
                auto str_line = str.substr(0, line_length);

                LineCacheItem &line = GetCachedParagraphLayout(str_line, state);
                if (line.layout != nullptr) {
                        state = line.state_after;
                        line.layout->Reflow();
                } else {
                        /* Line is new, layout it */
                        FontState old_state = state;

#if defined(WITH_ICU_I18N) && defined(WITH_HARFBUZZ)
                        if (line.layout == nullptr) {
                                GetLayouter<ICUParagraphLayoutFactory>(line, str_line, state);
                                if (line.layout == nullptr) {
                                        state = old_state;
                                }
                        }
#endif

#ifdef WITH_UNISCRIBE
                        if (line.layout == nullptr) {
                                GetLayouter<UniscribeParagraphLayoutFactory>(line, str_line, state);
                                if (line.layout == nullptr) {
                                        state = old_state;
                                }
                        }
#endif

#ifdef WITH_COCOA
                        if (line.layout == nullptr) {
                                GetLayouter<CoreTextParagraphLayoutFactory>(line, str_line, state);
                                if (line.layout == nullptr) {
                                        state = old_state;
                                }
                        }
#endif

                        if (line.layout == nullptr) {
                                GetLayouter<FallbackParagraphLayoutFactory>(line, str_line, state);
                        }
                }

                /* Move all lines into a local cache so we can reuse them later on more easily. */
                for (;;) {
                        auto l = line.layout->NextLine(maxw);
                        if (l == nullptr) break;
                        this->push_back(std::move(l));
                }

                /* Break out if this was the last line. */
                if (line_length == std::string_view::npos) {
                        break;
                }

                /* Go to the next line. */
                str.remove_prefix(line_length + 1);
        }
}

/**
 * Get the boundaries of this paragraph.
 * @return The boundaries.
 */
Dimension Layouter::GetBounds()
{
        Dimension d = { 0, 0 };
        for (const auto &l : *this) {
                d.width = std::max<uint>(d.width, l->GetWidth());
                d.height += l->GetLeading();
        }
        return d;
}

/**
 * Test whether a character is a non-printable formatting code
 */
static bool IsConsumedFormattingCode(char32_t ch)
{
        if (ch >= SCC_BLUE && ch <= SCC_BLACK) return true;
        if (ch == SCC_PUSH_COLOUR) return true;
        if (ch == SCC_POP_COLOUR) return true;
        if (ch >= SCC_FIRST_FONT && ch <= SCC_LAST_FONT) return true;
        // All other characters defined in Unicode standard are assumed to be non-consumed.
        return false;
}

/**
 * Get the position of a character in the layout.
 * @param ch Character to get the position of. Must be an iterator of the string passed to the constructor.
 * @return Upper left corner of the character relative to the start of the string.
 * @note Will only work right for single-line strings.
 */
ParagraphLayouter::Position Layouter::GetCharPosition(std::string_view::const_iterator ch) const
{
        const auto &line = this->front();

        /* Pointer to the end-of-string marker? Return total line width. */
        if (ch == this->string.end()) {
                Point p = {_current_text_dir == TD_LTR ? line->GetWidth() : 0, 0};
                return p;
        }

        /* Find the code point index which corresponds to the char
         * pointer into our UTF-8 source string. */
        size_t index = 0;
        auto str = this->string.begin();
        while (str < ch) {
                char32_t c = Utf8Consume(str);
                if (!IsConsumedFormattingCode(c)) index += line->GetInternalCharLength(c);
        }

        /* Initial position, returned if character not found. */
        const ParagraphLayouter::Position initial_position = Point{_current_text_dir == TD_LTR ? 0 : line->GetWidth(), 0};
        const ParagraphLayouter::Position *position = &initial_position;

        /* We couldn't find the code point index. */
        if (str != ch) return *position;

        /* Valid character. */

        /* Scan all runs until we've found our code point index. */
        size_t best_index = SIZE_MAX;
        for (int run_index = 0; run_index < line->CountRuns(); run_index++) {
                const ParagraphLayouter::VisualRun &run = line->GetVisualRun(run_index);
                const auto &positions = run.GetPositions();
                const auto &charmap = run.GetGlyphToCharMap();

                auto itp = positions.begin();
                for (auto it = charmap.begin(); it != charmap.end(); ++it, ++itp) {
                        const size_t cur_index = static_cast<size_t>(*it);
                        /* Found exact character match? */
                        if (cur_index == index) return *itp;

                        /* If the character we are looking for has been combined with other characters to form a ligature then
                         * we may not be able to find an exact match. We don't actually know if our character is part of a
                         * ligature. In this case we will aim to select the first character of the ligature instead, so the best
                         * index is the index nearest to but lower than the desired index. */
                        if (cur_index < index && (best_index < cur_index || best_index == SIZE_MAX)) {
                                best_index = cur_index;
                                position = &*itp;
                        }
                }
        }

        /* At the end of the run but still didn't find our character so probably a trailing ligature, use the last found position. */
        return *position;
}

/**
 * Get the character that is at a pixel position in the first line of the layouted text.
 * @param x Position in the string.
 * @param line_index Which line of the layout to search
 * @return String offset of the position (bytes) or -1 if no character is at the position.
 */
ptrdiff_t Layouter::GetCharAtPosition(int x, size_t line_index) const
{
        if (line_index >= this->size()) return -1;

        const auto &line = this->at(line_index);

        for (int run_index = 0; run_index < line->CountRuns(); run_index++) {
                const ParagraphLayouter::VisualRun &run = line->GetVisualRun(run_index);
                const auto &glyphs = run.GetGlyphs();
                const auto &positions = run.GetPositions();
                const auto &charmap = run.GetGlyphToCharMap();

                for (int i = 0; i < run.GetGlyphCount(); i++) {
                        /* Not a valid glyph (empty). */
                        if (glyphs[i] == 0xFFFF) continue;

                        int begin_x = positions[i].left;
                        int end_x   = positions[i].right + 1;

                        if (IsInsideMM(x, begin_x, end_x)) {
                                /* Found our glyph, now convert to UTF-8 string index. */
                                size_t index = charmap[i];

                                size_t cur_idx = 0;
                                for (auto str = this->string.begin(); str != this->string.end();) {
                                        if (cur_idx == index) return str - this->string.begin();

                                        char32_t c = Utf8Consume(str);
                                        if (!IsConsumedFormattingCode(c)) cur_idx += line->GetInternalCharLength(c);
                                }
                        }
                }
        }

        return -1;
}

/**
 * Get a static font instance.
 */
Font *Layouter::GetFont(FontSize size, TextColour colour)
{
        FontColourMap::iterator it = fonts[size].find(colour);
        if (it != fonts[size].end()) return it->second.get();

        fonts[size][colour] = std::make_unique<Font>(size, colour);
        return fonts[size][colour].get();
}

/**
 * Perform initialization of layout engine.
 */
void Layouter::Initialize()
{
#if defined(WITH_ICU_I18N) && defined(WITH_HARFBUZZ)
        ICUParagraphLayoutFactory::InitializeLayouter();
#endif /* WITH_ICU_I18N && WITH_HARFBUZZ */
}

/**
 * Reset cached font information.
 * @param size Font size to reset.
 */
void Layouter::ResetFontCache(FontSize size)
{
        fonts[size].clear();

        /* We must reset the linecache since it references the just freed fonts */
        ResetLineCache();

#if defined(WITH_UNISCRIBE)
        UniscribeResetScriptCache(size);
#endif
#if defined(WITH_COCOA)
        MacOSResetScriptCache(size);
#endif
}

/**
 * Get reference to cache item.
 * If the item does not exist yet, it is default constructed.
 * @param str Source string of the line (including colour and font size codes).
 * @param state State of the font at the beginning of the line.
 * @return Reference to cache item.
 */
Layouter::LineCacheItem &Layouter::GetCachedParagraphLayout(std::string_view str, const FontState &state)
{
        if (linecache == nullptr) {
                /* Create linecache on first access to avoid trouble with initialisation order of static variables. */
                linecache = new LineCache();
        }

        if (auto match = linecache->find(LineCacheQuery{state, str});
                match != linecache->end()) {
                return match->second;
        }

        /* Create missing entry */
        LineCacheKey key;
        key.state_before = state;
        key.str.assign(str);
        return (*linecache)[std::move(key)];
}

/**
 * Clear line cache.
 */
void Layouter::ResetLineCache()
{
        if (linecache != nullptr) linecache->clear();
}

/**
 * Reduce the size of linecache if necessary to prevent infinite growth.
 */
void Layouter::ReduceLineCache()
{
        if (linecache != nullptr) {
                /* TODO LRU cache would be fancy, but not exactly necessary */
                if (linecache->size() > 4096) ResetLineCache();
        }
}

/**
 * Get the leading corner of a character in a single-line string relative
 * to the start of the string.
 * @param str String containing the character.
 * @param ch Pointer to the character in the string.
 * @param start_fontsize Font size to start the text with.
 * @return Upper left corner of the glyph associated with the character.
 */
ParagraphLayouter::Position GetCharPosInString(std::string_view str, const char *ch, FontSize start_fontsize)
{
        /* Ensure "ch" is inside "str" or at the exact end. */
        assert(ch >= str.data() && (ch - str.data()) <= static_cast<ptrdiff_t>(str.size()));
        auto it_ch = str.begin() + (ch - str.data());

        Layouter layout(str, INT32_MAX, start_fontsize);
        return layout.GetCharPosition(it_ch);
}

/**
 * Get the character from a string that is drawn at a specific position.
 * @param str String to test.
 * @param x Position relative to the start of the string.
 * @param start_fontsize Font size to start the text with.
 * @return Index of the character position or -1 if there is no character at the position.
 */
ptrdiff_t GetCharAtPosition(std::string_view str, int x, FontSize start_fontsize)
{
        if (x < 0) return -1;

        Layouter layout(str, INT32_MAX, start_fontsize);
        return layout.GetCharAtPosition(x, 0);
}